Handwheel assembly for sewing machines

ABSTRACT

A handwheel assembly comprising a plastic outer shroud formed with a radial lug disposed for register with a radial channel or slot formed in a driven pulley to prevent relative rotary movement therebetween. The shroud is concentric with the pulley, which includes a hub that extends through and partly beyond a central opening formed in the shroud for receiving a push-on retainer having prongs that engage the pulley hub thereby to secure it axially relative to the shroud.

o h United States Patent 1151 3,6 1 1 99 Watson et a1. 51 Mn. 11,

[ HANDWHEEL ASSEMBLY FOR [56] defences Cited] SEWING MACHINES UNITED STATES PATENTS 1 Inventors: William Alexander Watson, Dumocher; 307,631 11/1884 Cleaveland ..74/230.7

Malcolm Mack, Glasgow, both Scmland 319,844 6/1885 Partridge ..152/402 [73] Assignee: The Singer Company, Elizabethport F., 323'635 8/1885 Chapm WM/2307 Ni 2,701,971 2/1955 Carter et a] ..74/230.7 1 Filed! J 1970 Primary Examiner-William F. ODea Assistant Examiner-F. D. Shoemaker LN 448 4 [21] App 0 2 AttorneyMarshall.l. Breen and Chester A. Williams, Jr. [30] Foreign Application Priority Data [57] ABSTRACT Oct. 28, 1969 Great Britain ..52,704 A handwheel assembly comprising a plastic outer shroud formed with a radial lug disposed for register with a radial [52] US. Cl ..74/230.7, 74/552, 287/5203 channel or slot formed in a driven pulley to prevent relative [5 l 1 Int. Cl ..F 16h 55/46 rotary movement therebetween. The shroud is concentric with [58] Field ofSearch ..74/552,553,572,573,230.1l, the pulley, which includes a hub that extends through and partly beyond a central opening formed in the shroud for receiving a push-on retainer having prongs that engage the pulley hub thereby to secure it axially relative to the shroud.

2 Claims, 3 Drawing Figures PATENTEDJAM 81972 30835099 l5 Fig. I.

iINVENTORS William A. Watson Malcolm Muck wmuess:

7ZWZTORNEY HANDWIIEEI, ASSEMBLY FOR SEWING MACHINES BACKGROUND OF THE INVENTION This invention pertains to an assembly for a handwheel, preferably made of plastic, capable of use with a sewing machine, wherein the plastic handwheel shroud is secured to the pulley in a relatively simple manner that not only is economically desirable, but also is completely dependably for its intended purpose and facilitates assembly of the sewing machine.

The prior art is replete with handwheel assemblies and constructions that attempt to provide an economically desirable and mechanically dependable arrangement for securing the handwheel shroud to the pulley. For the most part these prior art assemblies have been unsuccessful in providing the sewing machine manufacturer with a desirable arrangement. A substantial number of these prior art assemblies are relatively complicated to assemble, which adds to the cost of the handwheel and consequently, the overall cost of the sewing machine. Further, generally prior art sewing machine handwheels are made totally from cast iron and are painted with a hard enamel to enhance their aesthetic appearance. To avoid any possible chipping or scratching of the enamel during assembly of the sewing machine, the assembly line is set up such that the painted handwheel that is to be included in the machine for sale to the public is assembled to the machine arm shaft at the very end of the assembly line. It is necessary at a point during assembly of the machine to test its operability and therefore, a handwheel is required to connect the drive means to the driven arm shaft. Toward this end it is necessary to assembly a dummy handwheel to the arm shaft. When the machine reaches the end of the assembly line then the dummy handwheel is removed and replaced by the painted handwheel. It is readily apparent that the foregoing prior art method of assembly is an involved and costly procedure, and therefore adds to the consumers cost of the machine.

SUMMARY OF THE INVENTION The present invention comprises a novel and improved handwheel assembly that overcomes the above discussed prior art deficiencies and more, by providing a handwheel assembly that does not require the use of a dummy handwheel, thereby eliminating the assembly and disassembly thereof for operability test purposes and avoiding any possible marring of the final handwheel. Broadly, the handwheel assembly of the present invention comprises a pulley and a shroud adapted to be fastened thereto near the end of the assembly line. The pulley may be mounted on the machine arm shaft in the usual manner at a convenient point in the assembly line prior to the location where it is desired to test the operability of the machine. The pulley is all that is required to operably connect the drive belt between the driving means and the arm shaft, and may be secured in place on the arm shaft by a conventional clamp motion stop nut assembly. When the machine has been assembled and passed the necessary tests, all that remains is to assemble the shroud to the pulley thereby to provide an aesthetically desirable'cover for the pulley and other internal mechanism located at the end of the arm shaft. To assemble the shroud the clamp motion stop nut assembly is removed and the shroud is secured to the pulley in accordance with the present invention. The pulley is formed with a channel or slot that is designed to receive a lug formed on the plastic shroud thereby to prevent any significant amount of relative rotational movement. Once the shroud is placed in juxtaposition on the pulley a retaining member is placed in operable engagement with the pulley to secure the pulley axially relative to the shroud. Thus, there has been provided a novel and improved handwheel construction and arrangement that is relatively simple and economically desirable, and substantially expedites assembly of the sewing machine.

Accordingly, a primary object of the present invention is to provide an improved handwheel assembly suitable for use with a sewing machine.

Another object of this invention is to provide an improved handwheel assembly having novel means for securing the plastic shroud portion to the metallic pulley and for preventing any substantial relative movement therebetween.

A further object of this invention is to provide an improved sewing machine handwheel including novel means for preventing relative movement both in a rotary and axial direction.

Having in mind the above and other objects that will be evident from an understanding of the disclosure, the invention comprises the combination and arrangement of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectional view taken through a portion of a family type sewing machine having a handwheel em bodying the present invention;

FIG. 2 is a partial end elevation view of the handwheel assembly taken along the line 2-2 of FIG. l; and

FIG. 3 is an enlarged sectional view showing a portion of the handwheel assembly of FIG. ll.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the accompanying drawings, wherein similar parts are designated by the same reference character, there is illustrated in FIG. 1 a standard sewing machine, portions of which are illustrated, including .a bracket arm 10 having a bushing 11 mounted in flange 12 of the bracket arm for journably supporting an arm shaft 13 driven by suitable con ventional means, such as an electric: motor (not shown) mounted in the sewing machine standard 14. The arm shaft 13 is driven through a belt 15 of which at one end operably is connected with the motor output shaft and at the other end operably engages a peripheral annular groove 16 formed in a pulley member 17 which in the present invention is disclosed as being made of cast iron and forms part of a handwheel as sembly generally designated 18. It is understood that the pulley 117 may be made of material other than cast iron so long as the pulley is capable of performing its usual counterbalancing function in the sewing machine.

The handwheel assembly 18 comprises the cast iron pulley member 17 and a shroud 19, preferably made of suitably plastic material. The pulley I7 includes a hub portion 20 extending from one face of the pulley and being fonned with an open-ended bore 21 extending axially through the pulley. The pulley 17 is provided at its periphery with a pair of diagonally spaced identical channels or slots 22 and 23 which are cut into an axially extended flange or shelf 24 of the pulley 117. It will be apparent from the following description that these slots may be formed in the face or hub of the pulley as an alternative to the presently disclosed preferred arrangement. Each of the slots 22 and 23 comprises respectively a pair of axial walls 25-26 and 27-28, and a radial bottom surface 29 and 30. The radial surfaces 29 and 30 each have an outward downwardly sloping configuration, which is of a nonfunctional nature and relates only to the particular method of forming the slots. The use of two diagonally opposed slots gives the pulley a symmetrical balanced configuration that ensures proper balance of the handwheel assembly as it turns with arm shaft. The plastic shroud 19 includes a curved main surface 31 having a central aperture 32 defined by an adjacent flat annular surface 33 and integrally formed with a peripherally disposed rim as having an inner annular surface 35. Formed on the surface 35 is a radially disposed lug 36 that is elongated with the main axis thereof extending in an axial direction and having a taperedlike cross section that is slightly bulbous at each of its free corners as viewed in FIG. 2. The lug tapers inwardly in an outward radial direction to facilitate proper assembly of the shroud 19 to the pulley 17, that is, to ensure that any sharp comers formed in cutting the slots 22 and 23 will clear the comers formed on the plastic shroud. It is within the scope of this invention to locate the lug other than as disclosed. For example, if the slots were located on the face or hub of the pulley then the lug would be disposed on the shroud so that it would be capable of register with one of the slots. Thus, in the present preferred embodiment the shroud 19 is assembled to the cast iron pulley 17 by aligning the tapered lug 36 with one of the slots 22-23 and bringing the two parts into contiguous relationship. The diameter of the annular surface 35 is designed such that when the pulley 17 and the shroud 19 are assembled the latter temporarily will be held in place by reason of a slight friction fit between the surface 35 and the adjacent pulley surface. Further, although the invention discloses the slot and lug formed on the pulley and shroud,

' respectively, the situation may be reversed so that the lug is formed on the pulley and the slots formed on the shroud.

To fixedly secure the shroud to the pulley there is provided a push-on retainer 37 made of spring metal and including a plurality of inward facing annularly spaced prongs 38. With the pulley l7 assembled to the shroud 19 of the hub of the former extends through the central opening 32 and slightly beyond the flat annular surface 33. To secure the shroud axially to the pulley, that is to prevent any relative axial movement, the retainer 37 is pushed onto the extended portion of the hub 20 by means of a suitable tool whereupon thefree ends of the prongs 38, which slope slightly outward toward the extended hub portion relative to the flat surface 33, engage the adjacent hub surface. The free edges of the prongs 38 have a radius that is slightly less than the radius of the outer surface of the extended hub portion so that the retainer prongs resiliently engage the wall surface and tend to bite into the hub surface upon an attempt to remove the retainer. It is possible to remove the retainer 37 if it is desired to disassemble the handwheel, however, a substantial amount of effort is required. The most convenient way of removing the retainer would be to pry it oh" by means of a sharp pointed instrument. The relative radial dimensions of the retainer and the extended hub portion are such as to prevent the retainer from becoming loose or falling off during normal use of the handwheel for its intended function. Thus, from the above it is seem that undesirable relative movement of the shroud relative to the pulley is precluded both radially by reason of the lug-slot coaction and axially by reason of the retainer-hub coaction.

The handwheel assembly is assembled to the main arm shaft in a conventional manner by means of a clamp motion stop nut assembly 39. The handwheel assembly is mounted on a bushing 40 secured to the shaft by a screw 41. The annular shoulder 42 of the bushing 40 properly locates the assembly on the shaft by limiting the extent of its inward axial movement. The free end of the bushing 40 extends past the end of the arm shaft and is threaded internally for receiving the stop nut assembly 39 whereupon the handwheel assembly is secured to the shaft.

It is to be understood that the present disclosure relates to a preferred embodiment of our invention which is for purpose of illustration only and is not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thus disclosed the nature of our invention, what we claim herein is:

1. A handwheel assembly for use with a sewing machine having a main shaft, said handwheel assembly having a first member comprising a plastic shroud formed with a central opening and including an annular rim, a second member comprising a pulley being concentrically located relative to said shroud whereby said pulley and said shroud have a common axis, said pulley including an annular flange disposed in juxtaposition relative to said rim, at least one lug formed on one of said members and at lest one lug-receiving slot formed on the other of said members between said first member and said second member, said lug being disposed in register with said lug-receiving slot thereby to prevent relative rotary movement between said pulley and said shroud, said pulley including a hub that extends axially through and has a terminal portion extending slightly beyond said central opening, retainer means located adjacent said central opening for operably engaging said terminal portion, thereby to prevent axial movement between said shroud and said pulley.

2. A handwheel assembly according to claim 1 wherein said means comprises an annular retainer made of spring metal and having inwardly extending spaced fingers disposed in operably contact with said terminal portion of said hub, thereby to prevent relative axial movement between said shroud and said pulley. 

1. A handwheel assembly for use with a sewing machine having a main shaft, said handwheel assembly having a first member comprising a plastic shroud formed with a central opening and including an annular rim, a second member comprising a pulley being concentrically located relative to said shroud whereby said pulley and said shroud have a common axis, said pulley including an annular flange disposed in juxtaposition relative to said rim, at least one lug formed on one of said members and at lest one lug-receiving slot formed on the other of said members between said first member and said second member, said lug being disposed in register with said lug-receiving slot thereby to prevent relative rotary movement between said pulley and said shroud, said pulley including a hub that extends axially through and has a terminal portion extending slightly beyond said central opening, retainer means located adjacent said central opening for operably engaging said terminal portion, thereby to prevent axial movement between said shroud and said pulley.
 2. A handwheel assembly according to claim 1 wherein said means comprises an annular retainer made of spring metal and having inwardly extending spaced fingers disposed in operably contact with said terminal portion of said hub, thereby to prevent relative axial movement between said shroud and said pulley. 